Table 5. Daily Infant Intakes of Human Milk Amino Acids are Associated with Infant Body Composition at 0.5 - 6 Months of Age.

Linear mixed-effects models included infant weight-for-length z-score (WLZ), fat mass index (FMI), and fat free mass index (FFMI) over the first 6 months of life (time points 0.5, 2, and 6 months) as the dependent variables and infants' intakes of human milk amino acids (μmol/day) as the fixed effects. Model covariates included: infant age, infant birth weight, infant sex (FMI and FFMI models only), maternal BMI, gestational weight gain, maternal race, delivery mode (vaginal or C-section), and breastfeeding status. Random effects included: participant identification number, to account for repeated measures. Asp = aspartic acid, C-C = cystine, Gln = glutamine, Glu = glutamic acid, His = histidine, and Ser = serine.

	Weight-for-Length Z-score		Fat Mass Index (kg fat mass / m2)		Fat Free Mass Index (kg fat free mass / m2)
Amino Acid Intake (μmol/day)	β	p-value	β	p-value	β	p-value
Asp	0.0024	0.093	0.0038	0.011	0.0034	0.011
C-C	0.0103	0.088	0.0174	0.006	0.0163	0.004
Gln	0.0004	0.15	0.0011	<0.001	0.0007	0.009
Glu	0.0004	0.042	0.0005	0.005	0.0004	0.026
His	0.0080	0.039	0.0106	0.008	0.0088	0.015
Ser	0.0011	0.23	0.0029	0.002	0.0014	0.088